Heart failure can occur when the left ventricle of the heart becomes enlarged and dilated as a result of one or more of various etiologies. Initial causes of heart failure can include chronic hypertension, myocardial infarction, mitral valve incompetency, and other dilated cardiomyopathies. With each of these conditions, the heart is forced to overexert itself in order to provide a cardiac output demanded by the body during various demand states. The result can be an enlarged left ventricle.
A dilated or enlarged heart, and particularly a dilated or enlarged left ventricle, can significantly increase tension and stress in heart walls both during diastolic filling and systolic contraction, which contributes to further dilatation or enlargement of chambers of the heart. Prior treatments for heart failure include pharmacological treatments, assist devices such as pumps, and surgical treatments such as heart transplant, dynamic cardiomyoplasty, and Batista partial left ventriculectomy. These prior treatments are described briefly in U.S. Pat. No. 5,961,440, entitled “Heart Wall Tension Reduction Apparatus and Method,” issued on Oct. 5, 1999, the entirety of which is incorporated by reference herein.
A more recent concept for treating heart failure applies one or more splints onto the heart, to reduce myocardial muscular stresses encountered during pumping. Examples of such approaches are disclosed in U.S. Pat. No. 7,766,812, entitled “Methods and devices for improving mitral valve function,” issued on Aug. 3, 2010, the entirety of which is incorporated herein by reference. One example includes one or more transventricular splints placed across the left ventricle. Each splint may include a tension member extending across the ventricle with anchors disposed on opposite ends of the tension member and placed on the external surface of the heart.
Interventional cardiac procedures in humans generally require a specific access point, and the access point can be limited due to anatomic constraints. A needle or other instrument may need to be inserted through the access point, advanced to the heart without unnecessarily injuring nearby tissues and structures along the way, and then inserted into the heart. In treating mitral valve incompetency, mitral valve regurgitation, and other similar conditions, the needle or other instrument may be advanced across the right ventricle of the heart, passed through the septal wall or septum between the right ventricle and the left ventricle, extended across the left ventricle, and then passed through the posterior wall of the left ventricle. It may be beneficial to perform mitral valve treatments under live echocardiography imaging, so as to enable the surgeon to correctly orient the needle or other instrument during puncturing of the heart and/or other steps in the procedure/treatment. However, it is important not to cause undue trauma and, among other things, ensure that the access point into the patient, entry point into the heart, and any puncture points or incisions should be as small in size as possible so as to reduce trauma to the patient and reduce the time required for recovery. Current epicardial echocardiography probes are not well configured for mitral valve treatments through small access points (e.g., punctures, incisions, holes, etc.). Among other things, there is insufficient room in the access points for insertion of epicardial echocardiography probes, thus limiting visibility during treatment (e.g., during puncturing the heart wall and/or septum). Further, epicardial echocardiography probes are not well suited for being inserted into a small access points or entry points associated with various treatments of the heart (e.g., they are not well suited for treatment of mitral valve incompetencies, mitral valve regurgitation, and other similar conditions), and are not well suited for precise imaging during advancing a needle or other instrument across the right ventricle of the heart, through a small opening/puncture in the septal wall or septum, across the left ventricle, and then passed through the posterior wall of the left ventricle. Also, the probes may provide too narrow of a viewing range. Thus, it would be desirable to have better treatment methods using better configured imaging equipment that provide greater access and visibility to the surgeon during medical treatment, thereby imparting greater benefit to the patient.
The methods, systems, devices, apparatuses, instruments, etc. described herein may be used for medical treatment, for treatment of conditions of the human heart, and for improving heart valve function.